Process and apparatus for forming piston rings



June 12, 1923. 1,458,248

H. R. SEIFERT PROCESS AND APPARATUS FOR FORMING PISTON RINGS Filed July 18, 1921 2 Sheefs-Sheet l June 12, 1923. 1,458,248

H. R. SEIFERT PROCESS AND APPARATUS FOR FORMING PISTON RINGS Filed July 18 1921 Sheets-Sheet 2 Fatented dune l2, 1%233.

UNHTED stares HENRY R. SEIFERT, OF EAST ELLSWORTH, WISCONSIN.

PROCESS AND APPARATUS FOR FORMING PISTON RINGS.

Application filed July 18, 1921.

Ellsworth, in the county of Pierce and State of Wisconsin, have invented certain new and useful Improvements in Processes and Apparatuses for Forming Piston Rings; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My present invention relates to an improved process and apparatus for forming piston rings and has for its object to provide such a ring, the end portions of which primarily project outward of the diameter of the major portion of the ring. These end portions, when the ring is compressed in a cylinder, are pressed inward by their engagement with the cylinder wall and exert a yielding force tending to expand the ring and thereby cause the same to closely engage the cylinder wall throughout the entire circumference and thus form a tight joint be tween the ring and cylinder wall to prevent leakage of the fuel mixture during compression and the pumping of oil in the cylinders and also to insure equal wear between the ring and cylinder so that their contacting surfaces remain true and the joint, therebetween, tight.

To the above end, the invention consists of the novel devices and combinations of devices, hereinafter described and defined in the claims. v

In the accompanying drawings which illustrate the invention, like characters indicate like parts throughout the several views.

Referring to the drawings Fig. 1 is a view in side elevation of a ring as primarily cast and before a joint is formed therein;

Fig. 2 is a view in side elevation of the ring after the joint is formed therein and applied in a clamp for compressing the same;

Fig. 3 is a view corresponding to Fig. '2. with the exception that the clamp has been adjusted to compress the ring;

Fig. 4 is an outer face view of the ring and clamp, as shown in Fig. 3:

Fig. 5 is an elevation of a mandrel having mounted thereon. a plurality of rings to certain of which are still applied the clamps Serial No. 485,686.

some parts being broken away and other parts being sectioned;

Fig. 6 is a modified clamp; and

Fig. 7 is a perspective view of the finished ring.

The improved process of forming piston rings, first consists in casting, or otherwise, forming a continuous unbroken ring 10 having a greater circumference than that required when the ring is complete. A segment of this ring 10, substantially between the radial lines X, is formed on an inset eccentric 11, or in other words, on a flatter curve or curves than the balance or major portion of the ring, as shown in Fig. 1. The circle on which the major portion of the ring 10 is formed is extended through the arc of the inset eccentric portion 11, as indicated by broken lines in Fig. 1. This. inset eccentric portion 11, for example, in a threeand-three-fourths by one-quarter standard Ford piston ring is radially inset on its shortest diameter Y, say twenty-four-onethousandths of an inch. The length of the inset eccentric portion 11, of course, is only approximate and may vary one way or the other.

The ring 10 is primarily of such shape that after ajoint is formed therein and the ring compressed, it assumes a true circle or substantially, a true circle. Preferably. as. shown. the inset eccentric portion 11 is inset, both externally and internally, and hence, the ring 10 has a constant thickness throughout its entire circumference. In some instances, however, a ring may be formed by insetting only its internal surface within the eccentric portion 11.

A joint 12 is next formed in the ring 10, which includes severing said ring on the shortest diameter Y of its inset eccentric portion 11. Preferably, this joint 12 comprises reduced laterally ofi'set ends 13 and seats 14, the former of which, when the ring is compressed, overlap and enter said seats. The process of forming such a joint is fully described and broadly claimed in an application filed by me under date of July 23, 1921, S. N. 487,041, and entitled Machine for forming piston rings and process of producing the same.

The ends of the ring 10 are next further temporarily inset, say seven one-thousandths. following the example already set, by an inward radial pressure applied at the periphery ofthe joint 12 while the ring 10 is held compressed and against expansion or distortioncircumferentially outward of the inset eccentric portion 11. Various devices may be employed for thus further insetting the ends .of the ring. For instance, there is shown in the drawings, a clamp 15, which consists of a semicircular section 16, to the ends of which two quadrantal sections. 17 are, hinged at 18 for opening and closing movement in the plane of the clamp.

' The free ends of the clamp sections 17 are connected and drawn together, as shown, by a thumb-nut-equipped bolt 19, which extends through bores in the outturned circumferentially spaced ends 20 of said sections and has pivoted to its head, a lever 21 having a cam head 22 arranged to engage one of the ends 20, as an abutment, to draw the clamp sections 17 toward each other. This means of connecting the clamp sections 17 avoids adjusting the nut on the bolt 19 each time the clamp 15 is applied to a ring. To compensate fQIf F IiIlgS varying slightly in circumference',"}3 a coiled spring 23, encircling the bolt-19, is arranged to be compressed be tween the nut on the bolt and the respective clamp end 21 where the clamp is set. The tension of the spring 23 must, of course, have sufiicient tension to hold the clamp sections 17 set. When the lever 21 is moved into a position to set the clamp sections 17, the same is held'in an operative position against one of the clamp sections17, and to release the clamp, it is only necessary to swing said lever outward.

The internal or ring-engaging surface of the clamp, as shown in Figs. 2- and 3, is a true circle or substantially a true circle, except for a radially inset abutment24 midway between the hinged joints 14 and arranged to engage the ring 10 at its joint 12, when held in the clamp 15, and press the same inward. This abutment 24, as shown, is formed by flattening the internal curvature of the clamp section 16 throughout an arc of substantially the same length as the inset eccentric portion.

In Fig. 6, is shown a modified abutment in the form of a set screw 25 having screwthreaded engagement with the clamp section 16 at a point midway between the hinges 18 and arranged to impinge against the ends of the ring and spring the same inward a distance, which is variable, at will, when the clamp 15 is set. Preferably, the screw abutment 25 will be provided with a micrometer adjustment, but for the purpose of this case, it is not thought necessary to show the same. In the modified construction shown in Fig. 6, the internal surface of the clamp 15 may be a true circle.

The contact between the clamp 15 and the ring 10 is such that there is no strain applied to the ring 10 by the clamp 15, ex-

cept at its ends, where the same is'sprung inward'by the abutment 24. With a ring held in the clamp 15, the internal surface thereof may be smoothed up if it is rough.

A multiplicity or rings 10, individually held in the clamps 15, is next placed on the mandrel 26, the diameter of which is substantially the same as the internal diameters of the rings when compressed in the.

clamps 15, This mandrel 26 is of such length as to receive and hold any desired number of rings 10, as indicated in Fig. 5. On one end of the body of the mandrel 26 is a head 27, which affords a stop shoulder for the. rings 10, and on the other end thereof, is a reduced screw-threaded stud 28, to which is applied a nut 29. A follower 30, of the same diameter as the head 27, is interposed between the nut 29 and the adjacent end of the body of the mandrel 26.

By tightening the nut 29 on the stud 28,.

the rings 10-may be frictionally clamped, the one against the other, between the head 27 and follower 30. This frictional engagement to hold the same against any radial movement, as an entirety thereon, in case there should be any play between the rings 10 and mandrel 26.

After the clamps 15 have been removed from the rings 10, themandrel 26 is placed in a lathe with the lathe centers seated in holes 31, provided therefor, in the head 27 and stud' 28. The peripheries of the rings 10 are then ground or cut to a true circle throughout their entire circumference, by any suitable tool or stone. When the rings 10 are released from the mandrel 26,v the ends thereof will s ring outward beyond the true circle of the rings 10, when held com ressed. In placing the rings 10 in a cylin er, the same are held compressed and when released, the ends thereof will again tend to spring outward and by their engagement-with the cylinder wall, will exert a yielding force under strain to circumferentially expand the rings and thereby cause the same to engage the periphery of the cylinderwallthroughout its entire circumference and form ti ht joints between the piston rings and cylin er, as previously stated.

What I claim is:

1. The process of making piston rings which consists of forming a ring with ends ranging the rings 10 on the mandrel 26 is arranged to overlap when compressed, forming the inner surface of the ring at said ends with an inset eccentric portion, compressing the ring and springing its ends inward, holding the ring while compressed with its ends sprung inward, and cutting the periphery of the ring, while compressed andits ends sprung inward, to a true circle.

2. The process defined in claim 1 in Which the internal surface of the ring, when compressed, is substantially a true circle.

3. The process of making piston rings which consists of forming an endless ring with an inset eccentric portion, transversely dividing the ring on substantially the shortest diameter of said eccentric portion and forming joint members on the ends thereof arranged to overlap when the ring is compressed, compressing the ring and springing its ends inward, holding the ring compressed with its ends sprung inward, and cutting the periphery of the ring, while compressed and its ends sprung inward, to a true circle.

4. The process of making piston rings which consists of forming an endless ring having an inset segmental eccentric portion, transversely dividing the ring On substantially the shortest diameter of said eccentric portion and forming joint members on the ends thereof arranged to overlap when the ring is compressed, compressing the ring and springing its ends inward, holding the ring compressed with its ends sprung inward, and cutting the periphery of the ring while compressed and its ends sprung inward to a-true circle.

5. A device for use in forming piston rings, including a clamp applicable to the periphery of a ring for compressing the same and having an abutment arranged toengage a ring at its ends and spring the same inward, and means for holding the ring compressed with its ends sprung inward to permit the removal of the clamp.

6. A device for use in forming piston rings, including a clamp applicable to the periphery of a ring for compressing the same and having an adjustable abutment ar ranged to engage a ring at its ends and spring the same inward, and means for holding the ring compressed with its ends sprung inward to permit the removal of the clamp.

7. A device for use in forming piston rings including an annular clamp which consists of a semi-circular section having an abutment on its inner surface, two quadruple sections hinged to the ends of the semicircular section for opening and closing movements in the plane of the clamp, and means for connecting and drawing the free ends of the quadruple sections toward each other.

8. The structure defined in claim 7 in which said means is adjustable.

9. The structure defined in claim 7 in which said means is adjustable and can be operated to release the quadruple sections without changing the adjustment.

10. The structure defined in claim 7 in which said means yieldingly holds the quadruple sections.

In testimony whereof I afiix my signature' HENRY R. SEIFERT. 

